FIG. 10 illustrates a conventional biopsy device 1000 which includes an outer sheath assembly 1010 and an inner cannula assembly 1020. The outer sheath assembly 1010 includes an outer cannula 1012, a body 1014, and a handle 1016. A proximal opening 1018 is provided in the proximal end of the handle 1016.
The inner cannula assembly 1020 includes an inner cannula 1022 extending distally from an inner cannula locking hub 1024. A proximal opening 1026 is provided in the proximal end of inner cannula assembly 1020. The inner cannula assembly 1020 further includes a closed, distal tissue penetrating tip 1028, adapted for piercing tissue, and a side tissue sample port 1029 disposed proximally of the tip 1028. The sample port 1029 communicates with a central lumen extending the length of cannula 1022 to the proximal opening 1026.
The proximal opening 1018 of the outer sheath assembly 1010 allows for insertion of the inner cannula 1022 into the outer sheath assembly 1010. The relative position of the inner cannula 1022 to the outer sheath assembly 1010 can be maintained in a plurality of positions to provide a desired biopsy sampling mode.
The body 1014 further includes a biopsy method selection button 1017 and a release button 1019. The biopsy method selection button 1017 is used to select the desired biopsy sampling mode from the following: a fine needle aspiration mode of operation or a core sample mode of operation. In the fine needle aspiration mode of operation, a sample is withdrawn through the proximal opening 1026 via the sample port 1029 and the inner cannula 1022. In the core sample mode of operation, the release button 1019 is used to release the position of the outer cannula 1012 to obtain a core sample of tissue.
FIG. 10 illustrates the biopsy device 1000 in a position for obtaining a fine needle aspiration (FNA) sample through the proximal opening 1026 via the sample port 1029 and the inner cannula 1022. In this position, the outer cannula 1012 is partially retracted proximally relative to inner cannula 1022 by a distance less than the longitudinal length of the sample port 1029, in order to expose a portion, but not all of, the longitudinal length of the sample port 1029. This position is accomplished by pushing the selection button 1017 in a proximal direction.
In an insertion position, the outer cannula 1012 completely covers the sampling port 1029, thereby preventing tissue from entering the sample port 1029 during insertion or removal of the device 1000. In a core biopsy position, the outer cannula 1012 is retracted to a position in which the sampling port 1029 is fully exposed. Moving the selection button 1017 proximally causes the outer cannula 1012 to move proximally to fully expose the sample port 1029 in this position. In order to sever a core sample of tissue, the release button 1017 is depressed to cause the outer cannula 1012 to snap over the sample port 1029. As the outer cannula 1012 snaps over the sample port 1029, the outer cannula 1012 cuts through the tissue of interest, thereby severing any tissue disposed in the sample port 1029 to provide a core sample.